Laser-induced chemical reactions are the subject of an intense and rapidly growing research effort directed toward the production of novel chemical compounds, the development of energy efficient processing techniques, and isotope separation schemes. The direct approach in most of these studies is to attempt to excite a specific bond in a molecule with a laser photon in such a way that a specific bond is broken and another formed at the same place. The laser is applied as a molecular knife and welding tool in order to cut apart specific parts of molecules and weld them to others to bring about unique chemical reactions.
In such a well defined system of photons and absorbers, any collisional transfer of absorbed energy would be a loss in efficiency as well as a source of indiscriminate energy to be supplied to uncontrolled side reactions. Most laser chemistry experiments are designed in such a way as to keep the collisional energy transfer to a minimum. The technique of LPHP (Laser Powered Homogeneous Pyrolysis), developed by Shaub and Bauer, takes advantage of this energy transfer process of effect molecular decompositions. The absorption of energy from a focused or unfocused laser beam by a molecule of high stability can create very high local temperatures in the vicinity of the beam. The temperature, which is a function of the laser power and the absorption cross section, can easily be in excess of 1000.degree. C. If there are reasonable numbers of collisions of laser excited sensitizer molecules with reactant molecules which are less stable to thermal degradation or reaction and, in addition, which accept energy in an efficient transfer process from the laser excited molecules, there can be a rapid thermal reaction of the reactant molecules. The success of the energy transfer process depends on the stability of the sensitizer molecule. Thus, there are three criteria which must be satisfied by the sensitizer molecule: high absorbing cross section at a laser wavelength (the process need not be restricted to the utilization of CO.sub.2 lasers), high thermal stability in the sensitizer absorbing molecule, and a moderately fast collisional relaxation time.